As of Monday, Iran has surpassed limits on how much nuclear fuel the 2015 nuclear deal allowed it to possess. The relevant limitation restricted Iran to about a 660-pound stockpile of low-enriched uranium. The breach of this limitation does not, in and of itself, give Iran the ability to produce a nuclear weapon. While the Trump administration has not yet commented on this development, President Trump on Sunday made history by becoming the first U.S. president to cross the demilitarized zone into North Korea. His administration is also considering a new deal that would recognize North Korea as a nuclear power. The deal would institute a nuclear freeze, allowing North Korea to maintain the weapons it already has. During the Democratic Primary debates last week, the candidates discussed both of these countries. What does all this news mean for U.S. energy and security? We take listener calls and discuss with John Mearsheimer, the R. Wendell Harrison Distinguished Service Professor of Political Science and the co-director of the Program on International Security Policy at the University of Chicago.